Claims:We claim:
1. A device (110) to identify anomaly in gaseous fuel supply system (100) of a vehicle, said gaseous fuel supply system (100) comprises a reservoir (102) storing gaseous fuel, a High Pressure Shut-Off Valve (HP SOV) (104) located at an interface of said reservoir (102) and a High Pressure (HP) line (106), said HP line (106) is downstream of said reservoir (102) and connects said reservoir (102) to a pressure regulator (112), a Low Pressure (LP) SOV (114) connected downstream of said pressure regulator (112), and a Low Pressure (LP) line (116) connects said LP SOV (114) to a fuel injector (122), a HP sensor (108) and a LP sensor (120) are positioned in said HP line (106) and said LP line (116) respectively, characterized in that, said device (110) comprises a controller configured to
empty said LP line (116) and close said LP SOV (114);
monitor pressure in said LP line (116) through said LP sensor (120) for a threshold time and determine defect in said LP SOV (114) if a pressure is detected;
while no pressure is detected in said LP line (116) in said previous check, open said LP SOV (114) to maintain pressure before and after said LP SOV (114) and then close said LP SOV (114), monitor pressure in said LP line (116) as measured by said LP sensor (120) and determine a leakage in said filter (118) if a decrease in pressure is detected;
while no leakage is detected in said previous check, open said LP SOV (114) to equalize pressure throughout said LP line (116), monitor pressure by said LP sensor (120) and determine fault between said pressure regulator (112) and said LP SOV (114) if pressure reduction is detected;
while said pressure does not reduce in previous check, monitor pressure by said LP sensor (120) after opening said LP SOV (114), and determine a defect in said pressure regulator (112) if pressure monitored by said LP sensor (120) increases and a pressure monitored by said HP sensor (108) decreases;
while said pressure detected by said LP sensor (120) in previous check remains constant, monitor pressure by said HP sensor (108) and determine a leakage in said HP line (106) if said pressure reduces, and
while said HP SOV (104) is OFF, monitor pressure by said HP sensor (108) and determine a fault in said HP SOV (104) if said pressure increases.

2. The device (110) as claimed in claim 1, wherein said controller generates an alert whenever said anomaly is detected and exits from said sequence of check.

3. The device (110) as claimed in claim 1, is any one selected from a group comprising an Engine Control Unit (ECU) of said vehicle and an external diagnostic tool connected to said ECU of said vehicle.

4. The device (110) as claimed in claim 3, wherein said external diagnostic tool is connected to said ECU through anyone of an On Board Diagnostic (OBD) port, a Universal Serial Port (USB) and wireless connectivity.

5. The device (110) as claimed in claim 1, wherein said gaseous fuel is selected from a group comprising but not limited to a Compressed Natural Gas (CNG), Liquefied Natural Gas (LNG) and Liquefied Petroleum Gas (LPG).

6. A method for identifying anomaly in gaseous fuel supply system (100) of a vehicle, said gaseous fuel supply system (100) comprises a reservoir (102) storing gaseous fuel, a High Pressure Shut-Off Valve (HP SOV) (104) located at an interface of said reservoir (102) and a High Pressure (HP) line (106), said HP line (106) is downstream of said reservoir (102) and connects said reservoir (102) to a pressure regulator (112), a Low Pressure (LP) SOV (114) connected downstream of said pressure regulator (112), and a Low Pressure (LP) line (116) connects said LP SOV (114) to a fuel injector (122), a HP sensor (108) and a LP sensor (120) are positioned in said HP line (106) and said LP line (116) respectively, said method characterized by, a sequence of steps comprising
a) emptying said LP line (116) and closing said LP SOV (114);
b) monitoring pressure in said LP line (116) using said LP sensor (120) for a threshold time and determining defect in LP SOV (114) if a pressure detected;
c) while no pressure is detected in said LP line (116) in said step b), opening said LP SOV (114) to maintain pressure before and after said LP SOV (114) and then closing said LP SOV (114), monitoring pressure in said LP line (116) by said LP sensor (120) and determining a leakage in said filter (118) if a decrease in pressure is detected;
d) while no leakage found in step c), opening said LP SOV (114) to equalize pressure throughout said LP line (116), and determining leakage between said pressure regulator (112) and said LP SOV (114) if pressure is found to be decreasing;
e) while said pressure is does not decrease in said step d), opening said LP SOV (114) and monitoring pressure by said LP sensor (120), and determining a defect in said pressure regulator (112) if pressure monitored by said LP sensor (120) increases and a pressure monitored by said HP sensor (108) decreases;
f) while said pressure detected by said LP sensor (120) in step e) remains constant, monitoring pressure measured by said HP sensor (108) and determining leakage in said HP line (106) if pressure is detected to be decreasing, and
g) while said HP SOV (104) is OFF, monitoring pressure measured by said HP sensor (108) and determining a fault in said HP SOV (104) if said measured pressure increases.
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7. The method as claimed in claim 6, comprises generating an alert whenever said anomaly is detected and exiting said anomaly detection method.

8. The method as claimed in claim 6, wherein said steps are sequentially executed by any one device (110) selected from a group comprising an Engine Control Unit (ECU) of said vehicle and an external diagnostic tool connected to said ECU of said vehicle.

9. The method as claimed in claim 8, wherein said external diagnostic tool is connected to said ECU through anyone of an On-Board Diagnostic (OBD) port, a Universal Serial Port (USB) and wireless connectivity.

10. The method as claimed in claim 1, wherein said gaseous fuel is selected from a group comprising but not limited to a Compressed Natural Gas (CNG), Liquefied Natural Gas (LNG) and Liquefied Petroleum Gas (LPG).
, Description:Complete Specification:
The following specification describes and ascertains the nature of this invention and the manner in which it is to be performed:

Field of the invention:
[0001] The present invention relates to a device and method for identifying anomaly in gaseous fuel supply system of a vehicle.

Background of the invention:
[0002] In a gaseous fuel supply system of a vehicle, a Shut OFF Valve (SOV) can be used anywhere in the pressure lines and its operation can be controlled by a control unit. The SOV is normally closed when the engine is not running and opened only when the engine is running. However, to perform a diagnosis, the SOV can be opened for maximum of few seconds before the engine is started and should be closed after that. In case of any leakage in the low pressure line/section or high pressure line/section it is difficult to identify the location of the leakage point. Suppose if there is a leakage after regulator and before SOV it can be identified as fine leak in high pressure line. Similarly, in case there is an issue in the regulator it will be misinterpreted as high pressure leakage. In another case where there is issue in the SOV itself but is identified as regulator defect. Hence, a misdetection can lead to replacement of good working components. There is a need for a solution to identify proper location of the point where the leakage/fault exists.

[0003] A patent literature GB2513726 discloses a method and an apparatus for performing a leak test of a liquid gas fuel system of a motor vehicle. The method is described for performing a leak test of a liquid gas fuel system of a motor vehicle, wherein the liquid gas fuel system comprises a first section between a filling opening and a tank, a second section between an out-put of the tank and an evaporator, and a third section between an output of the evaporator and a fuel injection system, wherein the method comprises the following: -leak test of the third section by filling the third section with compressed air and monitoring the variation in pressure in the third section by means of a pressure sensor arranged on the fuel injection system; leak test of the second section by filling the second section with compressed air, venting the second section into the third section, and monitoring the variation in pressure in the third section by means of pressure sensor arranged on the fuel injection system.

Brief description of the accompanying drawings:
[0004] An embodiment of the disclosure is described with reference to the following accompanying drawing,
[0005] Fig. 1 illustrates a block diagram of a gaseous fuel supply system of a vehicle with a device to identify anomaly, according to an embodiment of the present invention, and
[0006] Fig. 2 illustrates a method for identifying an anomaly in the gaseous fuel supply system of the vehicle, according to the present invention.

Detailed description of the embodiments:
[0007] Fig. 1 illustrates a block diagram of a gaseous fuel supply system of a vehicle with a device to identify anomaly, according to an embodiment of the present invention. The gaseous fuel supply system 100 comprises a reservoir 102 storing gaseous fuel, a High Pressure Shut-Off Valve (HP SOV) 104 located at the interface of the reservoir 102 and a High Pressure (HP) line 106. A manual valve is also provided as per the safety regulation. The HP line 106 is downstream of the reservoir 102 and fluidly connects the reservoir 102 to a pressure regulator 112. A Low Pressure (LP) SOV 114 is connected downstream of the pressure regulator 112, and a Low Pressure (LP) line 116 connects the LP SOV 114 to a fuel injector 122 through a filter 118. The filter 118 is either one or multiple. A HP sensor 108 and a LP sensor 120 are positioned on the HP line 106 and the LP line 116 respectively. A temperature sensor 128 is also provided. Further, a check valve 124 is provided in HP line 106 and a Pressure Relief Valve (PRV) 126 is provided between the pressure regulator 112 and the LP SOV 114. The check valve 124 enables the filling of tank through a connector (shown as a box to left of the check valve 124) and in only one direction. The PRV 126 ensures maintaining predetermined pressure in the LP line 116. In the system 100, the LP SOV 114 is used on the low pressure side after the mechanical pressure regulator 112, characterized in that, the device 110 comprises a controller configured to sequentially perform checks/tests to identify the anomaly. The anomaly corresponds to any one of leakage, defect, fault, malfunction etc. in the gaseous fuel supply system 100.

[0008] In accordance to an embodiment of the present invention, the controller is configured to empty the LP line 116 and close the LP SOV 114. The emptying the LP line 116 is done after/during an end of a drive cycle of the vehicle for initiating the checks/tests in next drive cycle, or at beginning of the drive cycle itself. Alternatively, the LP line 116 is emptied on request by a driver or an operator. The controller monitors pressure in the LP line 116 through the LP sensor 120 for a threshold time and determines defect in the LP SOV 114 if a pressure is detected. If no pressure is detected (in comparison to a threshold pressure), the LP SOV 114 is determined to be not defective. While no pressure is detected in the LP line 116 in the previous check, the controller opens the LP SOV 114 to maintain pressure before and after the LP SOV 114 and then closes the LP SOV 114. The controller then monitors the pressure measured in the LP line 116 by the LP sensor 120 and determines a leakage in the filter 118 or an injector 122 if a decrease in the pressure is detected. If there is no decrease in the pressure, then the controller determines no defect/fault/leakage through the filter 118 or the injector 122. Further, while no leakage is detected in the previous check, the controller opens the LP SOV 114 to equalize pressure throughout the LP line 116, and monitors pressure measured by the LP sensor 120. The controller determines a fault between the pressure regulator 112 and the LP SOV 114 if pressure is detected to be reducing. If the pressure does not reduce, the controller determines no fault in the pressure regulator 112.

[0009] Still further, while the pressure does not reduce in previous check, the controller monitors pressure as measured by the LP sensor 120 after opening the LP SOV 114. The controller determines a defect in the pressure regulator 112 if pressure monitored by the LP sensor 120 increases and a pressure monitored by the HP sensor 108 decreases, else the pressure regulator 112 is determined to be not having any defect. Furthermore, while the pressure detected by the LP sensor 120 in previous check remains constant, instead of increasing, the controller monitors pressure measured by the HP sensor 108 and determine a leakage in the HP line 106 if the pressure reduction is detected. Furthermore, while the HP SOV 104 is OFF, the controller monitors pressure as measured by the HP sensor 108 and determines a fault in the HP SOV 104 if pressure increase is detected, else the HP SOV 104 is determined to be having no defects. If no anomaly is determined by the controller (or the device 110), then all the checked/tested components are detected to be working fine and updated in memory element.

[0010] The controller comprises memory element such as Random Access Memory (RAM) and/or Read Only Memory (ROM), Analog-to-Digital Converter (ADC) and vice-versa Digital-to-Analog Convertor (DAC), clocks, timers and at least one processor (capable of implementing machine learning) connected with the each other and to other components through communication bus channels. The memory element is pre-stored with logics or instructions or programs or applications and/or threshold values, which is/are accessed by the at least one processor as per the defined routines. The internal components of the controller are not explained for being state of the art, and the same must not be understood in a limiting manner. The controller may also comprise communication units to communicate with a server or cloud through wireless or wired means such as Global System for Mobile Communications (GSM), 3G, 4G, 5G, Wi-Fi, Bluetooth, Ethernet, serial networks and the like.

[0011] In accordance to the present invention, the controller generates an alert whenever the anomaly is detected and exists from the sequence of check. The anomaly is also stored in the memory element for future reference or transmitted to a server. The device 110 is any one selected from a group comprising an Engine Control Unit (ECU) of the vehicle and an external diagnostic tool connected to the ECU of the vehicle. Further, the external diagnostic tool is connected to the ECU through anyone of an On Board Diagnostic (OBD) port, a Universal Serial Port (USB) and wireless connectivity and not limited to the same. Other means known in the art to establish a communication are equally applicable.

[0012] In accordance to an embodiment of the present invention, the device 110 is implemented in a vehicle with gaseous fuel supply system 100 as described above. For example, four wheelers such as passenger cars, commercial vehicles such as lorry, light commercial vehicle (LCV), bus, and the like. The device 110 is retrofittable to existing vehicles as well. Further, the gaseous fuel is selected from a group comprising but not limited to a Compressed Natural Gas (CNG), Liquefied Natural Gas (LNG) and Liquefied Petroleum Gas (LPG), and other gaseous fuel and a combination thereof.

[0013] In accordance to an embodiment of the present invention, a working of the device 110 to identify the anomaly in the gaseous fuel supply system 100 is provided and must not be understood in limiting sense. The existing gaseous fuel supply system 100 uses electric LP SOV 114 for safety purpose. The LP SOV 114 is closed when the engine is not running and opened when the engine is running. However, to perform the diagnosis of the valves and to check for the leakage of the gaseous fuel, the LP SOV 114 is allowed to be opened for a maximum of few seconds such as two seconds. The device 110 performs the diagnosis and leakage checks within the threshold time and closes the LP SOV 114 thereafter. The determination of the fault in the LP SOV 114 is explained. During the previous driving cycle, the pressure in the LP line 116 is completely emptied just before the engine stalls. In the next driving cycle as soon as a Key is turned ON, the device 110 monitors the pressure in the LP line 116 using the LP sensor 120 before opening the LP SOV 114. If there is any pressure sensed by the LP sensor 120 then the fault/defect in the LP SOV is determined to be present.

[0014] The determination of detecting the leakage between LP SOV 114 and the filter 118/injector 122 is explained. The device 110 opens both the HP SOV 104 and the LP SOV 114 and maintains the pressure (say 5 bar in both HP line 106 and the LP line 116). The device 110 normalizes the pressure in LP line 116 (e.g. 5bar), followed by closing both the HP SOV 104 and the LP SOV 114. The device 110 then monitors the pressure for calibratable time. If a decrease in pressure as monitored by the LP sensor 120 is detected, then there is a leakage in the LP line 116. If there is no pressure change then the device 110 opens the LP SOV 114. The pressure should remain same.

[0015] The determination of leakage between the pressure regulator 112 and the LP SOV 114 is explained. While no leakage is found in previous check, the device 110 opens the LP SOV 114 to equalize pressure throughout the LP line 116. The device 110 determines leakage between the pressure regulator 112 and the LP SOV if the pressure measured by the LP sensor 120 decreases.

[0016] The determination of defect/fault in the pressure regulator 112 is explained. The device 110 monitors the LP sensor 120 and the HP sensor 108, and if there is increase in pressure in LP line 116 and decrease in pressure in HP line 106, then there is defect in the pressure regulator 112. To confirm, the device 110 again keeps monitoring the pressure. It is confirmed when the pressure on the LP line 116 keeps increasing.

[0017] The determination of leakage in the HP line 106 is explained. In continuation to previous check, if there is no change in the pressure in LP line 116 and the pressure remains constant throughout the process but there is a decrease in pressure in HP line 106 then the device 110 determines and confirms the leakage in the HP line 106.

[0018] The determination of defect in the HP SOV 104 is explained. In continuation to previous check, the device 110 determines a defect in the HP SOV 104 if there is an increase in the pressure in the HP line 106, when the HP SOV 104 is closed/OFF.

[0019] Fig. 2 illustrates a method for identifying an anomaly in the gaseous fuel supply system of the vehicle, according to the present invention. The gaseous fuel supply system 100 comprises the reservoir 102 storing the gaseous fuel, the High Pressure Shut-Off Valve (HP SOV) 104 located at the interface of the reservoir 102 and the High Pressure (HP) line 106. The HP line 106 is downstream of the reservoir 102 and fluidly connects the reservoir 102 to the pressure regulator 112. The Low Pressure (LP) SOV 114 is connected downstream of the pressure regulator 112, and the Low Pressure (LP) line 116 connects the LP SOV 114 to the fuel injector 122. The HP line 106 is fit with the HP sensor 108 and the LP line 116 is fit with the LP sensor 120. The method is characterized by plurality of steps. A step a) comprises emptying the LP line 116 and closing said LP SOV 114. The emptying of the LP line 116 is either done at the end of the drive cycle for the next drive cycle or at the beginning of new drive cycle. A step b) comprises a sub-step 202, 204 and 206. The sub-step 202 comprises monitoring pressure in the LP line 116 using the LP sensor 120 for a threshold time. The sub-step 204 comprises detecting/checking presence of a pressure. If yes, then sub-step 206 is executed, which determines that the LP SOV 114 is defective. If No (i.e. no pressure detection), then it implies that the LP SOV 114 is functioning properly without any defect, and the method proceeds to step c). The step c) comprises sub-steps 208, 210 and 212. The sub-step 208 comprises opening the LP SOV 114 to maintain pressure before and after the LP SOV 114 and then closing the LP SOV 114. The sub-step 210 comprises monitoring and checking the pressure in the LP line 116 by the LP sensor 120. If Yes, the sub-step 212 comprises determining the leakage in the filter 118 or injector 122 if decrease in pressure is detected. If No, or the pressure does not decrease, then it implies that the filter 118 or the injector 122 are working fine without any defect/leakage. The method then proceeds to step d) which comprises sub-steps 214, 216 and 218. The sub-step 214 comprises opening the LP SOV 114 to equalize pressure throughout LP line 116. The sub-step 216 comprises monitoring and checking the pressure measured by the LP sensor 120. If yes, i.e. if the pressure is decreasing, the sub-step 218 comprises determining leakage between the pressure regulator 112 and the LP SOV 114. If No, then it implies there is no leakage therebetween. The method proceeds to step e) which comprises a sub-step 220, 222, and 224. The sub-step 220 comprises opening the LP SOV 114 and monitoring the pressure through LP sensor 120. The sub-step 222 comprises checking if the pressure monitored by the LP sensor 120 increases and the pressure monitored by the HP sensor 108 decreases. If Yes, then sub-step 224 comprises determining a fault in the pressure regulator 112. If No, it implies there is no defect in the pressure regulator 112. The method proceeds to step f) which comprises sub-steps 226 and 228. The sub-step 226 comprises while/if the pressure detected by the LP sensor 120 in step e) remains constant and the pressure detected by the HP sensor 108 decreases. If yes, then as per sub-step 228, a leakage in the HP line 106 is determined. If No, then it implies the HP line 106 is fine without leakage. The method proceeds to step g) which comprises sub-step 230 and 232. The sub-step 230 comprises switching OFF the HP SOV 104 and monitoring the pressure measured by the HP sensor 108. The sub-step 232 comprises determining a fault in the HP SOV 104 is the pressure increases. If No, then no issues are found in the gaseous fuel supply system 100.

[0020] The method also comprises generating the alert whenever the anomaly is detected and exiting the anomaly detection method without checking other/remaining steps. The steps are sequentially executed by any one device 110 selected from a group comprising the Engine Control Unit (ECU) of the vehicle and the external diagnostic tool connected to the ECU of the vehicle. The external diagnostic tool is connected to the ECU through any one of the On Board Diagnostic (OBD) port, the Universal Serial Port (USB) and wireless connectivity and other means known in the art. Further, the gaseous fuel is selected from a group comprising but not limited to the Compressed Natural Gas (CNG), the Liquefied Natural Gas (LNG), the Liquefied Petroleum Gas (LPG) and other fuels including combination thereof.

[0021] According to the present invention, a solution or strategy for detecting the accurate location of the anomaly in the gaseous fuel supply system 100 in the vehicle is provided. The device 110 or the method is implementable through existing Engine Management System (EMS) (also known as the ECU). The present invention enables to find the anomaly in very short duration without any inconvenience to the driver. Alternatively, the driver itself may trigger the checks if needed.

[0022] It should be understood that embodiments explained in the description above are only illustrative and do not limit the scope of this invention. Many such embodiments and other modifications and changes in the embodiment explained in the description are envisaged. The scope of the invention is only limited by the scope of the claims.